Automatic fuse-switch for telegraph or other circuits.



No. 700,989. v Patented May 27, I902.

c. A. srm sou.

AUTOMATIC FUSE SWITCH FOR TELEGRAPH OR OTHER CIRCUITS.

(Application filed Aug. 28, 1901.)

(No Model.)

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CLARENCE A. STIMPSON, OF PHILADELPHIA, PENNSYLVANIA.

AUTOMATIC FUSE-SWITCH FOR TELEGRAPH OR OTHER CIRCUITS.

SPECIFICATION formingpart of Letters Patent No. 700,989, dated May 2 1902- Applioation filed August 28,1901- lii l N '7 ,54 (N 1 1 1 To all? whom it may concern.-

Be it known that I, CLARENCE A. STIMPSON, of the city and county of Philadelphia, State of Pennsylvania, have invented an Improvement in Automatic Fuse-Switches for Telegraph or other Circuits, of which the following is a specification.

My invention has reference to an automatic fuse-switch for telegraph and other circuits; and it consists of certain improvements set out in the following specification and shown in the accompanying drawings, which form a part thereof.

In telegraph, telephone, and other circuits it frequently happens that the secondary fuses therein are blown by the entrance of lightning discharges of comparatively small current,but of a sufficiently great amperage to de stroy the fuse, thereby causing the circuits to remain open until new fuses are inserted, and thus in many cases losing the use of the line overnight. The currents to which I have particular reference are commonly designated as sneak-currents-namely, those of comparatively small voltage, but of just sufficiently high amperage to burn out the instruments in the office if permitted to flow for a sufficiently long period. These currents being too small to blow the usual line-fuses there is no way of preventing injury to the instruments from them unless additional small-capacity fuses be used or some means be employed especially directed to take care of this particular trouble. Where such fuses are used in the ordinary way, the blowing of such fuses left the lines open, as above pointed out.

The object of my invention is therefore to provide a suitable automatic fuse switch which upon the passage of a current of sufficient amperage will cause a fuse to be ruptured and open the circuit, but which will immediately thereafter again close the circuit and introduce into the line a second fuse similar to the one thus blown, so that the line is only interrupted for an exceedingly short period of time, but in which time the instruments have been protected. If the entering current instead of being from lightning was from some continuous source of energy, the second fuse would in turn be ruptured and the circuit left open. In this manner the instruments are positively protected under all conditions. This latter case would seldom happen, however, and the particular cause to be guarded against is in lightning discharges of small current strength, and it is rarely the case the lightning strikes twice in the same place in one storm, so that there is little likelihood of the second fuse being blown also. The percentage of safety, therefore, is very high and the liability of the circuit being frequently opened is exceedingly small.

In carrying out my invention I provide between two terminal binding-posts two sets of fuses of preferably the same capacity. Each of these fuses is electrically connected to one of the binding-posts. The other end of one of the fuses is connected with the free end of a spring-actuated movable arm, and the corresponding terminal of the remaining fuse is connected with an open-circuit contact, with which the movable arm is adapted to be brought into circuit in case of the rupture of the fuse connected with said movable arm. The support of said movable arm is electrically connected with the other binding-post. It will be seen that in this manner a current will normally pass through one binding-post and one of the fuses, through the movable arm, and out by the other binding-post. If this fuse is ruptured by lightning, the arm moves rapidly under the action of the spring and interrupts the are produced. The arm immediately thereafter closes the circuit through the other fuse and completes the line-circuit again with only a moment of interruption.

My invention will be better understood by reference to the drawings, in which- Figure l is a side elevation of a lightningarrester embodying my improvements. Fig. 2 is a plan view of same, and Fig. 3 is a diagram illustrating the electric circuits of the terminal station of a telegraph-line with my invention applied thereto.

Referring first to Fig. 3, L is the line-wire and includes the relay S, the key 5, and the line-battery R. The relay controls the local circuit T, including the sounder U. R is a fuse for rupturing the circuit upon the entrance of large currents. W is a lightningarrester, also for large currents, for diverting them to the ground by wire w before entering the telegraph instruments. A is my improved lightning-arrester or fuse-switch for smaller currents and is interposed between the lightning-arrester l/V and the telegraph instruments.

Referring now more particularly to Figs. 1 and 2, B is a base of porcelain or other refractory or insulating material. Upon this base at a considerable distance apart are s cured the terminal binding-posts C and C, to which the line-circuit L connects. D is a post electrically connected by wire L with the terminal binding-post O. E is a movable arm preferably pivoted to the post D and adapted to be swung from the position shown in full lines to the position shown in dotted lines, in which latter position it is in electrical connection with contact J, which may be suitably formed of springs. The arm E is automatically thrown to the dotted position by the spring c when released. It is normally held in the position shown in full lines by the fuse-wire G, attached at one end to the free end of arm E by the clamp H and connected at its other end to a binding-post F, electrically in circuit with the terminal post 0. M is a second fuse and is preferably of similar capacity to the fuse G. One end of this fuse M is clamped to binding-post K in circuit with the contact J, and the other end is clamped to binding-post 0 in electrical circuit with the terminal post 0 by wire N. The wires L and N are inclosed within the base 13. It will now be understood that the current passes from the post 0 over fuse G, arm E, wire L to post 0. If fuse G becomes blown or ruptured, the arm E is thrown over to contact J and then the circuit is completed from post 0 to post 0 by Wire N, fuse M, arm E, and wire L. By this construction it is evident that the blowing of the fuse G interrupts the line-circuit for an instant and then closes the line through a second and similar fuse, so as not to allow the line to remain open an appreciable length of time. The fuses G and M are made to fuse by a current of a little more ampere strength than is produced by the line-batteries, so that if any current materially greater in amperes than that of the line-battery passes over the line and attempts to enter the terminal station the fuse G will be blown at once and the current dissipated before injury to the relay or other instruments takes place. Such currents are of a strength that they would not blow the fuse R nor jump the lightning-arrester W to the ground, and they are commonly called sneak-currents, since they are of such low strength as to pass the protec'tion devices R and VV usually employed. Of course if these currents continued to flow from any cause the second fuse M would also be blown and then the line would remain open. This, however, would not occur unless the currents are due to some source of energy of continuous character, such as from a dynamo or storage battery. If they were due to lightning, the blowing off the fuse G would insure the closing the line-circuit through the fuse M, and this would remain intact unless a further lightning discharge struck the same line.

A point of importance to be noted is that the fuse G is vertical, and hence when it is blown the arm E swings laterally away from the line of the discharge, and therefore quickly destroys the arc. The swinging of the arm E laterally on a curve will insure complete rupture of the are even when the post D is comparatively near to the post F. In the case of the fuse M, however, the bindingposts K and 0 should be farther apart, as shown.

The proportions and shapes of the parts or distance apart of the several binding-posts and parts D and J may be varied as desired to suit the requirements of the apparatus to be protected, and while the fuses G and M may in some cases be five-ampere fuses they may be increased or decreased in capacity, as may be found necessary. I would also point out that while I have shown my invention as applied to a telegraph-line it may be applied to telephone or any other electrical circuit, either for carrying small or large currents.

l/Vhile I prefer the construction shown, as being excellently adapted to the purpose of my invention, the details may be varied without departing from the essential features thereof.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is'

1. In an automatic lightning-arrester or fuse-switch, the combination of a branching main conductor, a separate fuse connected to each of the branches of the conductor and arranged at widely-separated points, a contact fixedly supported and holding the free end of one of the fuses whereby it is supported at both ends, a second main conductor, a springactuated movable contact-arm having a support connected with said second main conductor and located intermediate of the lastmentioned or fixed contact and the terminal of the other fuse and having its free end dirooted laterally away from the fixed contact and secured to the free end of the last-mentioned fuse to hold it taut with its length directed laterally away from the other fuse and so that said arm is held normally out of contact with the fixed contact of the other fuse whereby the arm moves laterally away from the normal direction of the length of the fuse holding it when said fuse is ruptured and makes contact with the fixed contact of the other fuse.

2. In an automatic lightning-arrester or fuse-switch, the combination of a spring-actuated pivoted contact-arm E, a fuse-clamp F near one side of the pivoted end of the con tact-arm, a fuse G between said clamp and the free end of the contact-arm E so that the arm makes an acute angle with the fuse, a contact J upon the opposite side of the pivoted. end. of the contact-arm and adapted to receive it when released from the fuse G, a fuse M connecting with the contact J, and two terminals of a divided circuit one conmeeting with the pivoted contact-arm E and the other connecting with both the clamp F and the fuse M substantially as set forth.

3. In an automatic lightning-arrester or fuse-switch, the combination of a base of insulating material, two terminal binding-posts secured thereon two fuse-clamps electrically connected with one of said binding-posts, a spring-actuated pivoted switch-arm also carried by the base and between the fuse-clamps, an electric circuit between the switch-arm and the other of the terminal binding-posts, a fuse-clamp carried upon the free end of the switch-arm, a fuse between one of the first- CLARENCE A. STIMPSON,

Witnesses:

R, M. HUNTER, J. W. KENWoRTI-IY. 

